WM_SIZE

发送时间:当窗口大小改变时.
详细时间:1.当窗口大小改变时,如最大化,最小化,用鼠标拉伸窗口.
2.当窗口刚被创建时

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参数说明:
wParam:
Specifies the type of resizing requested.
通常用来向别的窗口发送消息时,需要指定的附加信息

Value	Meaning
SIZE_MAXHIDE	Message is sent to all pop-up windows when some other window is maximized.
SIZE_MAXSHOW	Message is sent to all pop-up windows when some other window has been restored to its former size.
SIZE_MINIMIZED	The window has been minimized.
Value	Meaning
SIZE_RESTORED	The window has been resized, but neither the SIZE_MINIMIZED nor SIZE_MAXIMIZED value applies.

lParam:
The low-order word of lParamspecifies the new width of the client area.
The high-order word of lParam specifies the new height of the client area.
note:
lParam和GetClientRect的功能一样,有时候WM_SIZE的效率要比使用GetClientRect高. 可以在程序中使用WM_SIZE来保存Client area的大小方便以后使用.

 

WM_SIZE后于WM_CREATE消息!!在窗口被创建时的顺序!
WM_SIZE附带的信息:

WM_SIZE 
fwSizeType = wParam;      // resizing flag 
nWidth = LOWORD(lParam);  // width of client area 
nHeight = HIWORD(lParam); // height of client area 

告诉我们Windows处理窗口大小变化后新窗口客户区的大小.
Message Cracker

void Cls_OnSize(HWND hwnd, UINT state, int cx, int cy)
...{
  //do ...
}

参数cx,cy是新窗口客户区的大小!宽度和高度

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